In an effort to increase productivity, some farm implements have been increased in size substantially in recent years. For example, some planters, cultivators, fertilizers and other farm implements have a working path width in excess of forty feet. To increase the maneuverability of this size implement for off field or road transit conditions. it is common to have some form of articulation of the toolbar support.
In this regard, a collapsible farm implement would commonly have a central support, such as a wheeled trailer arrangement, and two toolbars would be hinged to this central support to swing about vertical axes. The outboard end of the toolbar, remote from the hinged inboard connection could have a wheeled support or could be cantilevered with appropriate re-enforcing struts or the like from the central support. In either case, the operational field use position of the toolbars would have them generally parallel to one another and extended in a direction crosswise to the direction of the farm implement travel. The width from end tip to end tip of the respective toolbars could thus exceed forty feet.
The road transit position is provided by rotating each toolbar approximately 90.degree. toward one another, generally toward the rear of the implement, so that they then become parallel to one another but are extended in line with or parallel to the direction of the traffic. The collapsible condition of the implement would have a much narrower width, comparable to the width of the tractor, while the length obviously would be increased. Nonetheless the collapsed implement would have greatly increased maneuverability for travel down narrower roads, through narrow gates, around tighter turns, etc.
The problem yet remains however in maneuvering the implement, and the toolbars of the implement, between the opened or field use position and the collapsed or road transit position. It is sometimes exceedingly difficult to achieve this movement, in part because the site or field may not be level or may have a rough or uneven surface, and in part because of the sheer size or bulk of each toolbar. Frequently, the efforts of several people are needed to accomplish these collapsing or opening movements.
Of particular concern, the toolbars must be maintained in general synchronization relative to one another as they are opened or closed, or the outboard or trailing ends of the toolbars in effect can maneuver almost unwieldingly. In fact, it is possible for either of the trailing toolbars to swing in past its normal trailing position and become entangled with the other toolbar, and/or to become unstably located relative to the farm tractor. In summary, extreme difficulty can be experienced and great effort and care might be needed to correct the situation.
Moreover, certain tool elements that is in a planter for example, are quite lengthy in the direction parallel to the ground and crosswise to the toolbar. Thus, even when the toolbars are closed, the total width of the two sets of tool elements can easily exceed ten feet to again limit the maneuverability of the collapsed vehicle. It is sometimes possible to reduce this width by nesting the tool elements from the separate toolbars within one another. However, nesting cannot be used with some tool elements, like planters, so the overall width of the collapsed or closed implement is yet quite wide.